ExtensionState returns 4

I’m having trouble with dialparties.agi failing because it says the extension is unavailable. This is because the ExtensionState returns 4. Is there something I need to do to get it to work ?

I’ve got this in my extensions.conf for the troubled extension:
exten => 112,1,Macro(exten-vm,112,112)
exten => ${VM_PREFIX}112,1,Macro(vm,112)
exten => 112,hint,SIP/112

On a more general note, is there a way to trace the manager interface ?